As always take anything I say with a grain of salt, but he are my quibbles:
1. Why the second Mek? He doesn't have anything super special about him other than being way cheap at this point. Unless you plan to have him follow behind the Kans to repair any weapon destroyed results (remember in squadrons an immobilized result = destroyed) which might be worth considering.
2. Remove 10 boyz from one of your 30 boyz shoota units and move them to the 10 boy unit to have two units of 20 boyz instead. A 10 boy unit not in a Trukk is just asking for a couple wounds and a morale check to get the heck out of dodge. Additionally I would look for the points to upgrade that big choppa to another power klaw. The hidden power klaw on the nob is one of the most powerful weapons in the Ork arsenal.
3. Skorchas on kans are a tremendous waste of that fabulous
BS of 3 that the Kans have. Honestly I would highly consider getting some KMBs or Rokkits on those Kans to make use of that enhanced
BS.
4. I love Stormboyz. Mine always have terrible rokkit packs (I always roll a 1 for the movement, true story

), but I continue to use them until I figure them out and I break my rokkit pack die curse. All that aside, I find a mob of 20 to be a bit much. Only because Stormboyz have a huge bullseye on them. They are too fast and too threatening to let live so to survive they have to hug behind cover and behind other units to keep that 4+ cover save until it is time to jump past and get to kumpin. Personally I find 12-15 to be a better number that is easier to hide behind cover, but your tables make allow for full mobs of 20 boyz to stay out of sight or behind cover.